The present invention relates generally to the field of wafer production and, more particularly, to an apparatus and methods for cleaning a wafer.
The problem of wafer contamination has existed since the birth of wafer manufacturing. The yield on fully processed silicon wafers is inversely related to the defect density of the wafers. One way to decrease defect density is to use cleaning techniques that remove particle contaminants.
A problem faced by those working in the wafer manufacturing industry, however is to find an effective way to remove particles from wafers with efficiency and without damage to the wafers. Small particles are difficult to remove from wafers, for example, because, of the strong electrostatic forces between the particles and the substrate.
Modern wafer manufacturing facilities use stringent contamination control protocols. These protocols can include the use of clean room suits, latex gloves, highly purified ventilation systems, and the like. In combination with these protocols, modern manufacturing facilities use various methods of cleaning wafers. The most common methods used to clean contaminated wafers usually involve pressurized water jet scrubs, rotating wafer scrubbers, wet chemical baths and rinses and similar systems. These processes, however, are prone to damaging the wafer. Additionally, the chemical processes have inherent dangers associated with the use of chemicals such as sulfuric acid, ammonium hydroxide, isopropyl alcohol, and the like.
Other features and advantages of the present invention shall be apparent to those of ordinary skill in the art upon reference to the following detailed description taken in conjunction with the accompanying drawings.
The present invention-provides a method of cleaning a wafer. The method comprises suspending the wafer beneath a vacuum chuck. The vacuum chuck contains an acoustic wave emitter. The acoustic wave emitter is positioned within the vacuum chuck to prevent the acoustic wave emitter from contacting the surface of the wafer. The method further comprises applying acoustic waves to the wafer.
The present invention further provides a wafer cleaning apparatus. The apparatus can include a vacuum chuck and an acoustic wave emitter. The acoustic wave emitter can be contained within the vacuum chuck and positioned to prevent the acoustic wave emitter from contacting the surface of the wafer.
The present invention also provides a method of cleaning a wafer. The method can include the steps of suspending the wafer beneath a vacuum chuck. The vacuum chuck can contain an acoustic wave emitter. The acoustic wave emitter can be positioned within the vacuum chuck to prevent the acoustic wave emitter from contacting the surface of the wafer. The method can further include applying acoustic waves to the wafer. Additionally, the method can include directing a stream of cleaning liquid at a surface of the wafer, the stream of cleaning liquid having an angle of incidence of less than about 10 degrees.
The present invention can further provide a method of cleaning a wafer. The method can include the steps of mounting the wafer to a vacuum chuck. The vacuum chuck can contain an acoustic wave emitter. The acoustic wave emitter can be positioned within the vacuum chuck to prevent the acoustic wave emitter from contacting the surface of the wafer. The method can further include applying acoustic waves to the wafer.
The present invention may also provide a method of cleaning a wafer. The method can include the steps of mounting the wafer to a vacuum chuck. The vacuum chuck can contain an acoustic wave emitter. The acoustic wave emitter can be positioned within the vacuum chuck to prevent the acoustic wave emitter from contacting the surface of the wafer. The method can further include applying acoustic waves to the wafer. Additionally, the method can include directing a stream of water at a surface of the wafer, the stream of water having an angle of incidence of less than about 10 degrees.